The kidney function of the human body may failure for different reasons. The kidney has different functions which are crucial for survival, such as separation and transportation of waste products from the biological fluid e.g. blood, balancing the level of electrolytes in the body, and balancing the acid and base status in the body.
Failure of the kidney may be acute or chronic, and may be treated by different methods like transplantation of the organ or by dialysis treatment. In dialysis treatment the biological fluids are separated from the body and treated as extracorporeal fluid outside the human body. There are different methods of dialysis available, for example hemodialysis, hemofiltration, and hemodiafiltration. In common, they all clean the body from waste products like urea and deleterious compounds like uremic toxins.
Deleterious compounds, like protein bound toxins, may be present in different biological fluids like, for example, blood, blood plasma, peritoneal fluids. A part of the deleterious compounds bind to proteins present in the blood, such as albumins. The uremic toxins are in normal cases removed from the biological fluids by the kidney function, as well as by the liver function. However, there may be sitivations where the deleterious substances shall be removed from the biological fluid, and where this removal process shall take place external the human body. For example, the blood extracted from the body during dialysis treatment, should also be cleaned from deleterious compounds.
There are methods and means available for removal of the deleterious compounds. An apparatus for cleaning of extracorporeal blood is known from WO 2007/046757. In this apparatus the blood is fractioned into a first cleaned fraction and a second cleaned fraction. The second cleaned fraction is produced by removing toxins bound on proteins and/or toxins dissolved in the plasma.
In U.S. Pat. No. 7,615,158 B2 it is described a method for removing partially carrier bound substances from blood. The method described therein includes applying a pressure gradient across the membrane to create an ultrafiltration.
A method for removal of uremic toxins bound to albumin in blood of a patient is described in U.S. Pat. No. 8,206,591 B2. This method includes introducing a displacer substance into the blood such that the displacer substance displaces deleterious substances bound to the albumin. The unbound uremic toxins are then removed by extracorporeal renal displacement treatment before the blood is returned to the patient. The displacer substance is for example bilirubin. This method is suggested to be used when drugs, such as salicylate shall be removed from the blood.
However, there is a need to improve the possibilities to remove the deleterious compounds from the biological fluids. Therefore, further means are needed to separate and clean the extracorporeal biological fluids from uremic toxins.